JP2700518B2 - Induction hardening method for axial workpiece - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for induction hardening a shaft-shaped workpiece having a special shape .

[0002]

2. Description of the Related Art A conventional technique will be described below with reference to the drawings. 3 to 6 are views for explaining an example of a conventional technique and an example of a work. FIG. 3 is a longitudinal sectional view of a conventional heating coil and a longitudinal section of an axial work, and FIGS. b) and (c) are respectively AA line, BB line,
FIG. 3 is a cross-sectional view taken along the line CC. FIGS. 5A and 5B show a state in which the axis of the shaft-shaped work is bent so as to protrude downward and upward, respectively. FIG.
(A), (b), and (c) are each the small size shown in FIG.
FIG. 7 is a longitudinal sectional view of a small-diameter portion having a cross-sectional shape different from the diameter portion.
FIG. 5 is an external perspective view of a main part of the shaft-shaped work shown in FIGS.
You.

First, an axial workpiece 10 to which the method of the present invention is applied.
The shape of 0 will be described with reference to FIGS. 3, 4, and 7. FIG. Axial
The workpiece 100 has a substantially cylindrical large-diameter portion 101 and a large-diameter portion 1.
01 and small-diameter portions 111 and 112 integrally formed on both sides.
It has. The cross-sectional shape of the small diameter portions 111 and 112 is
Lower half circumference than the upper half circumference as shown in FIGS.
Is large, and the center of gravity 120 of the cross-sectional shape is the axis of the large-diameter portion 101.
It is separated downward from the core wire 109. The relationship between the radius R3 in the upper half circumference of the small diameter portion 111, the radius R2 in the lower half circumference, and the radius R1 of the large diameter portion 101 is R3 <R2 <.
R1.

[0004] To explain the entirety of the shaft-shaped work 100, a medium diameter portion 113 is formed on the small diameter portion 111 on the side opposite to the large diameter portion 101. The middle diameter portion 114, the small diameter portion 115, and the middle diameter portion 116
Are formed. And the large diameter part 101, the small diameter part 11
1, 112, medium diameter parts 113 and 114, small diameter part 115, and medium diameter part 116 are integrally formed. Medium diameter part 113
And 114 are similar to the cross- sectional shape of the small-diameter portion 111, but the diameter of the lower half circumference is slightly larger than the radius R1 of the large-diameter portion 101. In addition, the small diameter portion 115 and the medium diameter portion 116
The cross-sectional shape is cylindrical with the axis 109 as the center.

[0005] A straight hole 103 having a circular cross section and having a center axis 109 as the center of the circle has a middle diameter portion 113, a small diameter portion 111, a large diameter portion 101, a small diameter portion 112, a medium diameter portion 114, and a small diameter portion. 115
And a hole 104 is formed in the outer peripheral surface of the middle diameter portion 116 so as to reach the middle of the middle diameter portion 116.
Are drilled in the radial direction. A radial hole 105 communicating with the hole 103 is formed in the outer peripheral surface 102 of the large diameter portion 101.
Reference numeral 106 denotes a bolt hole formed in the end face of the middle diameter portion 116 in the direction of the axis 109.

Conventionally, the large-diameter portion of such a shaft-shaped workpiece 100
In order to form the hardened layer 108 by induction hardening the outer peripheral surface 102 of 101, an annular high-frequency heating coil having a cross section as shown in FIG. 3 (hereinafter, the high-frequency heating coil is also simply referred to as a heating coil)
200 is disposed so as to surround the outer peripheral surface 102 of the large-diameter portion 101 of the shaft-shaped work 100, and both ends of the shaft-shaped work 100 are rotatably supported. After rotating the heating coil 200 with a high frequency current for a predetermined time while rotating about the center, the quenching liquid injection hole 20 opened on the inner peripheral surface of the heating coil 200 while the shaft-shaped workpiece 100 is kept rotating.
From FIG. 2, when the quenching liquid L introduced into the hollow portion 201 inside the heating coil 200 is injected onto the outer peripheral surface 102 of the large diameter portion 101 and cooled, a hardened layer 108 is formed on the outer peripheral surface 102.

[0007] When the strain of the axial workpiece 100 in which the outer peripheral surface 102 of the large diameter portion 101 is hardened in this way is measured, FIG.
As shown in FIG. 3A, the shaft core wire 109 is generally bent so as to protrude downward (downward in FIG. 3) at the large diameter portion 101.

Generally, when the peripheral surface of a shaft-shaped work is quenched, the work bends so that the rapidly cooled peripheral surface protrudes. That is, in the case of the axial workpiece 100, since the lower half of the mass of the small diameter portions 111 and 112 is larger than the upper half of the mass, the heat generated in the large diameter portion 101 by the high frequency heating by the heating coil 200 is reduced. , 112, the large diameter portion 101 corresponding to the lower half circumference is transmitted to the mass and cooled faster than the large diameter portion 101 corresponding to the upper half circumference. Therefore, the shaft core wire 109 of the shaft-shaped work 100 is bent as shown in FIG.

[0009]

Therefore, in order to prevent bending of the shaft-shaped workpiece 100 after induction hardening as described above, before quenching, the shaft-like workpiece 100 must be previously bent in a direction opposite to the direction of bending after quenching. That is, as shown in FIG.
0 in the large diameter portion 101 (FIG. 3).
After being bent so as to protrude upward, the induction hardening as described above is performed.

However, the work of bending the axial workpiece in the direction opposite to the direction of bending after quenching before quenching is extremely time-consuming. The present invention was been developed in view of such circumstances, when induction hardening the outer peripheral surface of the large diameter portion of the workpiece, the shaft-shaped workpiece, the quenching before, the opposite direction to bend after quenching It is an object of the present invention to provide an induction hardening method for a shaft-like work which does not require labor for bending in a direction of.

[0011]

In order to solve the above-mentioned problems, the method of induction hardening a shaft-like workpiece according to the present invention uses a substantially cylindrical shape.
A large-diameter part and a small-diameter part formed on the side of the large-diameter part.
And the center of gravity of the cross-sectional shape of the small diameter portion is the axis of the large diameter portion.
Cyclic or an outer peripheral surface of the large diameter portion of the shaft-like workpiece away from the line
Is almost equally divided into an upper hollow part and a lower hollow part
The in induction hardening method of the shaft-shaped workpiece to be hardened by high-frequency heating coil, the said high-frequency heating coil diameter
After being arranged so as to surround the outer peripheral surface of the portion, the outer peripheral surface is heated by the high-frequency heating coil while rotating the axial work around the axis, and then the center of gravity and the
The line connecting the shaft core is almost vertical, and the center of gravity is
Stop the rotation of the shaft-shaped work at the position that comes down,
Liquid quenching liquid provided on the inner peripheral surface of the lower hollow part and the lower hollow part
The amount of quench liquid injected from the injection hole is lower in the upper hollow part.
It is characterized in that it is larger than the hollow part .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an example of an induction hardening apparatus capable of realizing the method of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of this device, and FIG. 2 is a perspective view.
As the workpiece, an axial workpiece 100 shown in FIG. 3 described in detail in the description of the related art is used.

As shown in FIGS. 1 and 2, the induction hardening apparatus is an annular, quadrangular cross-sectional tubular member which is disposed so as to face the large-diameter portion 101 of the shaft-shaped work 100 and surround the large-diameter portion 101. The heating coil 10 is provided. Heating coil 10
One side surface 13, the other side surface (not shown), outer peripheral surface 1
1, and a hollow portion surrounded by the inner peripheral surface 12 is divided by two partition plates 14 into an upper ( upper upper portion in FIG. 1) half upper hollow portion 22 and a substantially lower half lower hollow portion 32. It is divided. These upper hollow part 22 and lower part
A quenching liquid is introduced into the hollow part 32.

A pair of lead conductors 17 and 18 are connected to a division point of the heating coil 10 at the upper hollow portion .
An insulating plate 19 is inserted between the lead conductors 17 and 18. The heating coil 10 corresponding to the upper hollow portion 22
A number of quench liquid injection holes 21 for injecting the quench liquid L1 introduced into the upper hollow portion 22 are formed on the inner peripheral surface 12 of the quench liquid. The heating coil 1 corresponding to the lower hollow portion 32
A number of quenching liquid injection holes 31 for injecting the quenching liquid L2 introduced into the lower hollow portion 32 are formed on the inner peripheral surface 12 of the zero.

[0015] 23, to provide baked liquid inlet L1 to the upper hollow portion 22, a pair of coupler baked liquid inlet supply pipe 25 is connected, corresponding to the upper hollow portion 22 of the heating coil 10 It is attached to the outer peripheral surface 11. Also, 33
In order to supply the quenching liquid L2 to the lower hollow portion 32,
The coupler is connected to the quenching liquid supply pipe 35 and is attached to the outer peripheral surface 11 corresponding to the lower hollow portion 32 of the heating coil 10.

Reference numeral 28 denotes a pump for integrally sending out the quenching liquids L1 and L2.
6 is provided, the outlet side of the solenoid valve 26 is branched into two, one branch is connected to the coupler 23 via the valve 27 and piping 25 can change the flow rate, the upper hollow portion of the heating coil 10 The quenching liquid L1 is supplied to the pump 22. The other branch is connected to the coupler 33 via a valve 37 and a pipe 35 that can change the flow rate, and supplies the quenching liquid L2 to the lower hollow portion 32 of the heating coil 10. The opening degrees of the valves 27 and 37 are set so that the flow rate of the quenching liquid L1 injected from the quenching liquid injection hole 21 is larger than the flow rate of the quenching liquid L2 injected from the quenching liquid injection hole 31. Is set.

Next, a method of quenching the outer peripheral surface 102 of the large-diameter portion 101 of the shaft-shaped workpiece 100 by the induction hardening device will be described. First, the operation of the pump 28 is started. The solenoid valve 26 is closed. The valves 27 and 37 are each set to a predetermined opening degree so that the flow rate of the quenching liquid L1 is larger than the flow rate of the quenching liquid L2. Next, the axial work 100 is inserted and arranged in the heating coil 10 so that the inner peripheral surface 12 of the heating coil 10 surrounds the outer peripheral surface 102 of the large diameter portion 101, and both ends of the axial work 100 are rotatably supported. The shaft is rotated about the axis 109 by a device (not shown).

Next, the lead conductor 1 of the heating coil 10
A high-frequency current is supplied to the heating coil 10 from a high-frequency power source (not shown) connected between
1 is heated, and the center of gravity 120 is connected to the axis 109.
The line is substantially vertical, and the center of gravity 120 is
Rotation of the axial workpiece 100 to a position below
To stop. Hereinafter, the shaft-shaped workpiece 100 whose rotation has been stopped.
Is located in the cooling position.

Next, when the solenoid valve 26 is opened, the quenching liquid L1
Is injected through the valve 27, the supply pipe 25, the coupler 23, and the upper hollow portion 22 to the upper half of the outer peripheral surface 102 of the large diameter portion 101 from the quenching liquid injection hole 21. In addition, quenching liquid L2
Is injected through the valve 37, the supply pipe 35, the coupler 33, and the lower hollow portion 32 from the quench liquid injection hole 31 to the lower half of the outer peripheral surface 102 of the large diameter portion 101. Quenching liquid L1, L2
In both cases, after the injection for a predetermined time is performed, the electromagnetic valve 26 is closed to stop the injection of the quenching liquids L1 and L2, and the quenching ends.

At this time, as described above, the flow rate of the quenching liquid L2 is selected to be smaller than the flow rate of the quenching liquid L1 by the set opening degrees of the valves 27 and 37, so that the large diameter portion 101 Since the degree of cooling in the lower half of the outer peripheral surface 102 having a larger side mass is substantially equal to the degree of cooling in the upper half of the outer peripheral surface 102 having a smaller side mass of the large diameter portion 101, quenching is performed. Later, the shaft-shaped workpiece 100 as seen in the conventional quenching method
There is no bending around the large diameter portion 101.

In the above embodiment, the small diameter portions 111, 112
Although the case where the diameter of the lower half circumference is larger than the diameter of the upper half circumference has been described, the present invention is not limited to the half circumference such as the lower half circumference or the upper half circumference. For example, as shown in FIG. When the diameter of the lower 1/3 circumference is R2 and the diameter of the upper 2/3 circumference is R3, the flow rate of the quenching liquid L1 is equal to R2.
The flow rate can be adjusted within the range larger than the above flow rate to reduce the bending of the quenched axial workpiece. In addition, 121 is the center of gravity of the small diameter portion 111a.

Further, as shown in FIG.
In some cases, the cross-sectional shape in the direction perpendicular to the axial direction of 1b may be a circle having a radius R4 centered on the center 131. 122 is the small diameter part 111c
Is the center of gravity of the cross-sectional shape. Further, as shown in FIG. 6C, the cross-sectional shape of the small diameter portion 111c in the direction perpendicular to the axial direction is the center of gravity.
It can be oval with 123. The quenching liquid L can be applied to such an axial work having the small diameter portions 111b and 111c.
Within the range where the flow rate of 1 is larger than the flow rate of the quenching liquid L2, the respective flow rates can be adjusted to reduce the bending of the quenched axial workpiece.

The axial work taken in the above embodiment
In the vicinity of the outer peripheral surface 102 where the 100 large diameter portion 101 is hardened,
Although the holes 102 and 103 are provided, the method of quenching the outer peripheral surface 102 by the apparatus of the present embodiment can be performed as described above without being affected by the presence or absence of the holes 102 and 103.

[0024]

As described above, the present invention is substantially circular.
The columnar large diameter part and the small diameter part formed on the side of the large diameter part
And the center of gravity of the cross-sectional shape of the small diameter portion is the axis of the large diameter portion.
The outer peripheral surface of the large-diameter part of the shaft-like work that is away from the core wire is annular
And almost equally divided into an upper hollow part and a lower hollow part in a cylindrical shape
In induction hardening method of the shaft-shaped workpiece to be hardened by high-frequency heating coil, the size of the high-frequency heating coil
After arranging the outer peripheral surface of the diameter portion so as to surround the outer peripheral surface, the outer peripheral surface is heated by the high-frequency heating coil while rotating the shaft-shaped work about the axis, and then the center of gravity is moved forward.
The line connecting the shaft core is approximately vertical, and the center of gravity is
Also stop the rotation of the axial work at the position that comes down,
Quenching liquid provided on the inner peripheral surface of upper hollow part and lower hollow part
The amount of quenching liquid injected from the injection hole is
It is characterized in that it is larger than the lower hollow part .

Accordingly, when the outer peripheral surface of the large-diameter portion of the axial work is quenched by the induction hardening method of the present invention, the entire outer peripheral surface of the large-diameter portion has a substantially uniform temperature drop. As a result, bending after quenching does not occur. Therefore, it is not necessary to bend the shaft-shaped work which has been required conventionally before quenching.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of an induction hardening apparatus capable of realizing the induction hardening method of the present invention.

FIG. 2 is a perspective view of an embodiment of an induction hardening apparatus capable of realizing the induction hardening method of the present invention.

FIG. 3 is a longitudinal sectional view of a conventional heating coil and a longitudinal sectional view of a shaft-shaped work.

FIGS. 4A, 4B, and 4C are cross-sectional views taken along lines AA, BB, and CC of FIG. 3, respectively.

FIG. 5 is a drawing for explaining a conventional technique, and FIG.
(A) and (b) show a state where the axis of the shaft-shaped work is bent so as to protrude downward and upward, respectively.

6 (a), 6 (b), and 6 (c) each show a small diameter portion having a cross-sectional shape different from the small diameter portion shown in FIG.

FIG. 7 is an external perspective view of a main part of a shaft-shaped work.

[Explanation of symbols]

 10 Heating coil 14 Partition plate 21, 31 Quenching liquid injection hole 22 First hollow part 32 Second hollow part 100 Axial work 101 Large diameter part 102 Outer peripheral surface 109 Shaft core 111, 112, 111a, 111b, 111c Small diameter part 120 Center of gravity 130 Extension line L1, L2 Quenching liquid R1, R2, R3 Radius

Claims (1)

(57) [Claims] 1. A substantially cylindrical large-diameter portion and a side portion of the large-diameter portion.
And a cross-sectional shape of the small-diameter portion.
The outer peripheral surface of the large-diameter part of the shaft-shaped workpiece whose center of gravity is separated from the axis of the large-diameter part is annular and cylindrical, and the upper hollow part and the lower part
It is fired by a high-frequency heating coil that is almost equally divided into an empty part.
In induction hardening method of the shaft-shaped workpiece to be input, place the high frequency <br/> wave heating coil so as to surround the outer circumferential surface of the large diameter portion, rotating the shaft-like workpiece about said axis core After heating the outer peripheral surface by the high-frequency heating coil , the line connecting the center of gravity and the axis is substantially vertical,
And the center of gravity is below the shaft center line.
Stop the rotation, the upper hollow portion and the lower hollow portion
Quenching liquid injection amount injected from the quench liquid injection hole provided on the inner peripheral surface
The upper hollow part is more than the lower hollow part
Induction hardening method of the shaft-shaped workpiece, characterized in that the.